Balancing device for thrust-bearings.



kkov LD C. A. KROGH. BALANOING DBvIoB Pon THBUST BEARINGS. APPLICATION FILED MAB. 31, 1909. 992,005.

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G. A. KROGH.

BALANCING DEVICE FOB. THRUST BEARINGS.

APPLIOATION FILED MAR. 31, 1909.

Patented May 9, 1911.

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`o. A. KROGH. BALANOING DEVIOB FR THRUST BEARINGS.

APPLICATION FILED 16111.31, 1909.

Patented May 9, 1911.

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UNITED STATES PATENT OFFICE.

CARL A. KROG-H, OF SAN FRANCISCO, CALIFORNIA.

BALANCING DEVICE FOR THRUST-BEARINGS.

To all whom 'it may concern.'

Be it known that I, CARL A. KRoGH, of San Francisco, California, have invented certain new and useful Improvements in Balancing Devices for Thrust-Bearings, whereof the following is a specification. a

My invention is more particularly mtended for use with centrifugal pumps though applicable to other uses. In these pumps when running the suction tends to draw the impeller toward the suction side and it is to resist this tendency that my device is intended when used with such a pump.

In carrying out my invention as applied to a centrifugal pump, I connect a piston to the shaft of the pump at a convenient point,

which piston moves in a fixed cylinder. I also connect to the pump shaft a valve which admits water under pressure to said cylinder to act against said piston, in opposition to the draft of the suction of the pump. This is done by connecting the piston chamber with the pump discharge or other source of supply. I also, in some cases, connect the piston chamber with the suction of the pump or other point of exhaust, and arrange a valve which is opened when the pressure valve is closed, and retrogrades the piston.

In the accompanying drawings I have shown a centrifugal pump with my invention applied to it, the form shown being the preferable form, there being many other forms in which the invention may be used.

Figure 1 is a sectional elevation showing a pump with the balancing piston and chamber and a connection from the latter to the pump discharge. Fig. 2 is a cross section at the point 2, 2, of Fig. 1. Fig. 3 is an enlarged view showing the pressure valve and its connection to the pump shaft. Fig. 4 is a similar View showing a modified form of valve. Fig. 5 is the same showing another modication in the form of the valve.

1 represents the casing of the pump, 2 is t-he impeller rotating therein.

3 is the discharge chamber from which the pumped iuid passes away through a discharge, not shown.

4 is the suction opening from which fluid is drawn into the impeller through the central opening 5 therein, in the usual manner.

6 is the shaft of the pump to which the impeller wheel is made fast.

Above the suction 4, and surrounding the shaft 6, is a balancing chamber 7, which may Specification of Letters Patent.

App1ication filed March 31, 1909.

Patented May 9, 1911.

serial No. 486,992.

be formed as a part of the pump casing, if so desired. In the chamber and preferably near its lower part is a piston or plunger 8, which moves in a packing ring 9 that rests upon a seat 10. The piston 8 is secured to the shaft G by a set screw 11 or otherwise so that it partakcs of the longitudinal movement of the shaft, and it may rotate with the shaft or not, this being immaterial. Thus, when the pump is in operation there .is a tendency on the part of the suct-ion to draw the impeller upward toward the suction opening. If now a pressure be created tending to press the impeller downward, the suction will be balanced and the impeller will float, so to speak, in its casing, practically without friction and without wear. For the purpose of creating such a downward pressure, I connect the chamber 7 with the pump chamber 3 by a pipe 12, which conveys fluid under pressure to chamber 7 when the pump is running, and tends to force the piston 8, and with it the impeller, downward.

13 is a cross-head loose upon shaft 6, but caused to partake of the longitudinal movement of the shaft by a collar 14 upon the shaft on each side of it. The cross-head has two arms, one of which 15 engages a guide 1G on the casing of the chamber and serves to maintain the head in its proper radial position while permitting its free longitudinal motion.. The other arm 17 of the head carries a valve 18. In the form shown in Figs. 1 to 5 inclusive, this valve is a short pipe 18, sliding in a valveway 19, and surrounded by an annular passage 2O communicating with pipe 12. The tube 18 is perforated at 21, so that fluid may pass from the passage 20 into the tube 18 and out of the ends thereof into chamber 7 where it acts on piston 8 in the manner already described. As the piston is forced downward, carrying the shaft and t-he impeller with it, the tube 18 also moves downward in the valveway 19 and carries the openings 21 below passage 20, so that fluid ceases to enter chamber 7, being cut ofi'l therefrom. The impeller then remains floating until the leakage from chamber 7 permits it to rise again, when the described operation is repeated. For the purpose of taking up wear I provide the valve and valveway with a packing 22.

In pumping roily water, an objectionable amount of grit frequently accumulates in Chamber 7. With my invention this is easily got rid of, when the pump is at rest, and the pressure relieved from the chamber, by simply pushing up ring 9 from its seat 10, and washing the grit down into the pump. This operat-ion can be effected without opening the chamber, or the pump,

Vby simply raising shaft 6, which will raise piston 8, and ring 9 with it, and allow the contents of the chamber to run down around the piston into the pump suction. Vhen the pressure is in the chamber, when the pump is in action, the ring is held thereby against its seat, and movement of the shaft moves the piston in the ring, and does not raise the ring.

The piston, and the valve, being connected to the shaft by set screws, may be adjusted longitudinallythereon, and their positions changed as required by the exigencies of service. Also they may be disconnected for repair, or renewal or other purpose. And the piston, especially, if worn in one zone may be adjusted up or down on the shaft to bring another zone into action. Owing to the small size of these various parts, they are easily machined, and their construction thereby facilitated.

I claim 1. In a centrifugal pump, in combination with the impeller and its shaft, a pressure chamber surrounding the shaft, a movable septum adjustably connected to said shaft and movable under the pressure in said chamber, and a valve in said chamber adjustably connected to said movable septum and moved by the longitudinal movement thereof and operative to open and close a communication between said chamber and the source of pressure.

2. In a centrifugal pump, in combination with the impeller and its shaft, a pressure chamber on the suction side of the pump a piston connected to the shaft in said chamber and exposed on one side to the pressure therein and on its other side to the suction of the impeller, a projecting arm in said chamber connected to said shaft and moved by the longitudinal movement thereof and a valve mounted on said arm, and operative to open and close a communication between the chamber and a source of pressure.

3. In a centrifugal pump, in combination with the impeller and its shaft, a pressure chamber surrounding the shaft and having an `internal boss onY one side, a pressure pipe connecting the discharge of the pump with a channel in said boss, and a valve operated by the longitudinal movement of the shaft by an arm projecting therefrom and adapted to open and close said channel.

4;. In a centrifugal pump, in combination with the impeller and its shaft, a pressure chamber surrounding the shaft and having an internal boss on one side, a pressure pipe connecting the discharge of the pump with a channel in said boss, and a valve to open and close said channel, operated by'the longitudinal movement of said shaft by an arm projecting therefrom, and a guide on the inner wall of said chamber engaging said arm and operative to resist rotation thereof.

5. In a centrifugal pump, in combination with the impeller and its shaft, a pressure chamber surrounding the shaft, a hollow piston adjustably connected to said shaft and having one side exposed to the pressure in said chamber and on its other side to the suction of the pump, and a surrounding packing ring resting upon a seat in said chamber, a loose collar mounted on said shaft above said piston, provided with a projecting arm and a valve in said chamber' mounted on said arm and moved by the longitudinal movement of said shaft, and operative to open and close a communication between said chamber and the source of pressure.

In testimony that I claim the foregoing I have hereto set my hand in the presence of two witnesses this 10th of March, 1909.

CARL A. KROGH.

Witnesses:

F. W. KRoGi-I,

BATES.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

